The present invention is generally directed to devices, systems and methods for cutting and sealing tissue such as bone and soft tissue. The present invention may be particularly suitable for sinus applications and nasopharyngeal/laryngeal procedures and may combine or provide Transcollation® technology with a microdebrider device.
Devices, systems and methods according to the present disclosure may be suitable for a variety of procedures including ear, nose and throat (ENT) procedures, head and neck procedures, otology procedures, including otoneurologic procedures. The present disclosure may be suitable for a varient of other surgical procedures including mastoidectomies and mastoidotomies; nasopharyngeal and laryngeal procedures such as tonsillectomies, trachael procedures, adenoidectomies, laryngeal lesion removal, and polypectomies; for sinus procedures such as polypectomies, septoplasties, removals of septal spurs, anstrostomies, frontal sinus trephination and irrigation, frontal sinus opening, endoscopic DCR, correction of deviated septums and trans-sphenoidal procedures; rhinoplasty and removal of fatty tissue in the maxillary and mandibular regions of the face.
Sinus surgery is challenging due to its location to sensitive organs such as the eyes and brain, the relatively small size of the anatomy of interest to the surgeon, and the complexity of the typical procedures. Examples of debriders with mechanical cutting components are described in U.S. Pat. Nos. 5,685,838; 5,957,881 and 6,293,957. These devices are particularly successful for powered tissue cutting and removal during sinus surgery, but do not include any mechanism for sealing tissue to reduce the amount of bleeding from the procedure. Sealing tissue is especially desirable during sinus surgery which tends to be a complex and precision oriented practice.
Electrosurgical technology was introduced in the 1920's. In the late 1960's, isolated generator technology was introduced. In the late 1980's, the effect of RF lesion generation was well known. See e.g., Cosman et al., Radiofrequency lesion generation and its effect on tissue impedance, Applied Neurophysiology (1988) 51: 230-242. Radiofrequency ablation is successfully used in the treatment of unresectable solid tumors in the liver, lung, breast, kidney, adrenal glands, bone, and brain tissue. See e.g., Thanos et al., Image-Guided Radiofrequency Ablation of a Pancreatic Tumor with a New Triple Spiral-Shaped Electrode, Cardiovasc. Intervent. Radiol. (2010) 33:215-218.
The use of RF energy to ablate tumors or other tissue is known. See e.g., McGahan J P, Brock J M, Tesluk H et al., Hepatic ablation with use of radio-frequency electrocautery in the animal model. J Vasc Interv Radiol 1992; 3:291-297. Products capable of aggressive ablation can sometimes leave undesirable charring on tissue or stick to the tissue during a surgical procedure. Medical devices that combine mechanical cutting and an electrical component for cutting, ablating or coagulating tissue are described, for example, in U.S. Pat. Nos. 4,651,734 and 5,364,395.
Commercial medical devices that include monopolar ablation systems include the Invatec MIRAS RC, MIRAS TX and MIRAS LC systems previously available from Invatec of Italy. These systems included a probe, a grounding pad on the patient and a generator that provides energy in the range of 450 to 500 kHz. Other examples of RF bipolar ablation components for medical devices are disclosed in U.S. Pat. Nos. 5,366,446 and 5,697,536.
Medical devices are also used to ablate heart tissue with RF energy. See, e.g., Siefert et al. Radiofrequency Maze Ablation for Atrial Fibrillation, Circulation 90(4): I-594. Some patents describing RF ablation of heart tissue include U.S. Pat. Nos. 5,897,553, 6,063,081 and 6,165,174. Devices for RF ablation of cardiac tissue are typically much less aggressive than RF used to cut tissue as in many procedures on cardiac tissue, a surgeon only seeks to kill tissue instead of cutting or removing the tissue. Cardiac ablation of this type seeks to preserve the structural integrity of the cardiac tissue, but destroy the tissue's ability to transfer aberrant electrical signals that can disrupt the normal function of the heart.
Transcollation® technology, for example, the sealing energy supplied by the Aquamantys® System (available from Medtronic Advanced Energy of Portsmouth, N.H.) is a patented technology which stops bleeding and reduces blood loss during and after surgery and is a combination of radiofrequency (RF) energy and saline that provides hemostatic sealing of soft tissue and bone and may lower transfusion rates and reduce the need for other blood management products during or after surgery. Transcollation® technology integrates RF energy and saline to deliver controlled thermal energy to tissue. Coupling of saline and RF energy allows a device temperature to stay in a range which produces a tissue effect without the associated charring found in other ablation methods.
Other ablation devices include both mechanical cutting as well as ablation energy. For example, the PK Diego® powered dissector is commercially available from Gyms ENT of Bartlett, Tenn. This device utilizes two mechanical cutting blade components that are moveable relative to each other, one of which acts as an electrode in a bipolar ablation system. The distal end portion of the device includes six layers to accomplish mechanical cutting and electrical coagulation. The dual use of one of the components as both a mechanical, oscillating cutting element and a portion of the bipolar system of the device is problematic for several reasons. First, the arrangement exposes the sharp mechanical cutting component to tissue just when hemostasis is sought. In addition, the electrode arrangement does not provide for optimal application of energy for hemostasis since the energy is applied essentially at a perimeter or outer edge of a cut tissue area rather than being applied to a central location of the cut tissue. The arrangement of the device also requires more layers than necessary in the construction of a device with both sharp cutters and RF ablation features. The overabundance of layers can make it difficult to design a small or optimally-sized distal end. Generally speaking, the larger the distal end, the more difficult it is for the surgeon to visualize the working surfaces of the device. The use of six layers at the distal end of the system also interferes with close intimate contact between the tissue and the electrodes. Some examples of cutting devices are described in U.S. Pat. Nos. 7,854,736 and 7,674,263.
The Medtronic Straightshot® M4 Microdebrider uses sharp cutters to cut tissue, and suction to withdraw tissue. While tissue debridement with the Medtronic microdebrider system is a simple and safe technique, some bleeding may occur. The Medtronic microdebrider does not include a feature dedicated to promoting hemostasis or bleeding management. Thus, nasal packing is often used.